Bull Shark

The maximum length of bull sharks is believed to be about 3.5 m (11.5 ft) and the maximum weight, 230 kg (507 lb). Females are slightly larger than males, averaging 2.4 m (8 ft) in length and 130 kg (285 lb) in weight. The average length of males is 2.3 m (7.5 ft) with a weight of 95 kg (209 lb). Bull sharks are robust-bodied with a blunt, rounded snout. They have two dorsal fins. The first is large and triangular with a pointed or rounded tip. The second fin is about one third the height of the first fin. There is no skin ridge between the fins as is common in many other sharks. Their upper teeth are broad, triangular, and heavily serrated while those in their lower jaw are narrow, triangular, and finely serrated. The rounded eyes of these sharks are small compared to those of other gray sharks. These sharks are countershaded. They are pale to dark gray on their upper bodies, fading to white on their undersides. The dark tips on the fins of juveniles fade as the sharks mature.

Bull sharks live in a variety of habitats—salty, shallow, coastal waters in depths of 1-150 m (3.3-492 ft); bays and harbors; low salinity estuaries, lagoons and river mouths; and freshwater lakes and rivers. Although they can spend long periods of time in freshwater, it is doubtful that they spend their entire lives in such a habitat. Juveniles stay in estuaries and shallower coastal waters, gradually venturing out into deeper waters as they mature. They are solitary hunters, swimming sluggishly close to the bottom until prey appears. Then they can accelerate to a swimming speed of 19 km/hr (11.8 mph). They rarely show themselves at the water’s surface. Their extensive diet includes many prey items: bony fishes, turtles, crustaceans, cephalopods, marine mammals, birds, mollusks, and almost anything else they find, including garbage. While juveniles prefer bony fishes, the preference of adults is for cartilaginous fishes such as rays and other sharks, especially juvenile sand sharks that they seek out in shallow nursery grounds.

These sharks usually breed in the ocean and in estuaries but there is evidence that mating can take place in freshwater as well. Bull sharks reach sexual maturity when they are 5-6 years old. At this age, males measure 1.6-2.3 m (5.2-7.4 ft) in length, and females 1.8-2.3 m (5.9-7.5 ft). After a gestation period of 10-11 months, the female bull shark moves into an estuary where she delivers 1-13 live, free-swimming pups. The pups are 55-80 cm (21.6-31.5 in) long at birth.

Biology

Appearance

Reproduction